By Paul Carrel and Stine Jacobsen BERLIN/COPENHAGEN (Reuters) – The European Union on Wednesday promised a “robust” response to any intentional disruption of its energy infrastructure after saying it suspected sabotage was behind gas leaks discovered this week on subsea Russian pipelines to Europe. As gas spewed out under the Baltic Sea for a third day after first being detected, it remained far from clear who might be responsible for any sabotage of the Nord Stream pipelines that Russia and European partners spent billions of dollars building. Russia, which slashed gas deliveries to Europe af…